/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2009 by Red Hat Inc and/or its affiliates or by
* third-party contributors as indicated by either @author tags or express
* copyright attribution statements applied by the authors. All
* third-party contributions are distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.ejb.criteria.predicate;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.persistence.criteria.Expression;
import javax.persistence.criteria.Predicate;
import org.hibernate.ejb.criteria.CriteriaBuilderImpl;
import org.hibernate.ejb.criteria.CriteriaQueryCompiler;
import org.hibernate.ejb.criteria.ParameterRegistry;
import org.hibernate.ejb.criteria.Renderable;
/**
* A compound {@link Predicate predicate} is a grouping of other {@link Predicate predicates} in order to convert
* either a conjunction (logical AND) or a disjunction (logical OR).
*
* @author Steve Ebersole
*/
public class CompoundPredicate
extends AbstractPredicateImpl
implements Serializable {
private BooleanOperator operator;
private final List<Expression<Boolean>> expressions = new ArrayList<Expression<Boolean>>();
/**
* Constructs an empty conjunction or disjunction.
*
* @param criteriaBuilder The query builder from which this originates.
* @param operator Indicates whether this predicate will function
* as a conjunction or disjunction.
*/
public CompoundPredicate(CriteriaBuilderImpl criteriaBuilder, BooleanOperator operator) {
super( criteriaBuilder );
this.operator = operator;
}
/**
* Constructs a conjunction or disjunction over the given expressions.
*
* @param criteriaBuilder The query builder from which this originates.
* @param operator Indicates whether this predicate will function
* as a conjunction or disjunction.
* @param expressions The expressions to be grouped.
*/
public CompoundPredicate(
CriteriaBuilderImpl criteriaBuilder,
BooleanOperator operator,
Expression<Boolean>... expressions) {
this( criteriaBuilder, operator );
applyExpressions( expressions );
}
/**
* Constructs a conjunction or disjunction over the given expressions.
*
* @param criteriaBuilder The query builder from which this originates.
* @param operator Indicates whether this predicate will function
* as a conjunction or disjunction.
* @param expressions The expressions to be grouped.
*/
public CompoundPredicate(
CriteriaBuilderImpl criteriaBuilder,
BooleanOperator operator,
List<Expression<Boolean>> expressions) {
this( criteriaBuilder, operator );
applyExpressions( expressions );
}
private void applyExpressions(Expression<Boolean>... expressions) {
applyExpressions( Arrays.asList( expressions ) );
}
private void applyExpressions(List<Expression<Boolean>> expressions) {
this.expressions.clear();
this.expressions.addAll( expressions );
}
public BooleanOperator getOperator() {
return operator;
}
public List<Expression<Boolean>> getExpressions() {
return expressions;
}
public void registerParameters(ParameterRegistry registry) {
for ( Expression expression : getExpressions() ) {
Helper.possibleParameter( expression, registry );
}
}
public String render(CriteriaQueryCompiler.RenderingContext renderingContext) {
if ( getExpressions().size() == 0 ) {
boolean implicitTrue = getOperator() == BooleanOperator.AND;
if ( isNegated() ) {
implicitTrue = !implicitTrue;
}
return implicitTrue
? "1=1" // true
: "0=1"; // false
}
if ( getExpressions().size() == 1 ) {
return ( (Renderable) getExpressions().get( 0 ) ).render( renderingContext );
}
final StringBuilder buffer = new StringBuilder();
String sep = "";
for ( Expression expression : getExpressions() ) {
buffer.append( sep )
.append( "( " )
.append( ( (Renderable) expression ).render( renderingContext ) )
.append( " )" );
sep = operatorTextWithSeparator();
}
return buffer.toString();
}
private String operatorTextWithSeparator() {
return getOperator() == BooleanOperator.AND
? " and "
: " or ";
}
public String renderProjection(CriteriaQueryCompiler.RenderingContext renderingContext) {
return render( renderingContext );
}
/**
* Create negation of compound predicate by using logic rules:
* 1. not (x || y) is (not x && not y)
* 2. not (x && y) is (not x || not y)
*/
@Override
public Predicate not() {
toggleOperator();
for ( Expression expr : this.getExpressions() ) {
if ( Predicate.class.isInstance( expr ) ) {
( (Predicate) expr ).not();
}
}
return this;
}
private void toggleOperator() {
if ( this.operator == BooleanOperator.AND ) {
this.operator = BooleanOperator.OR;
}
else {
this.operator = BooleanOperator.AND;
}
}
}